Humans were designed to stand upright. And yet in this modern world, too many of us spend our days with our heads slumped over for a simple reason: we're staring at the tiny screen of a smartphone.

People spend an average of 2 to 4 hours each day with their neck bent at this unnatural angle while shooting off emails or texts. That's 700 to 1,400 hours a year. The success of social media is has led to an epidemic of ''bad smartphone posture''.